1. Institute of Geomatics, BOKU, Vienna, AT, Austria
2. Image Processing Laboratory (IPL), University of Valencia, Valencia, SP, Spain
3. Geosciences, University of Montana, Missoula, Montana, USA
4. Estación Experimental de Aula Dei (EEAD-CSIC), Zaragoza, SP, Spain
5. NTGS, University of Montana, Montana, Montana, USA
6. Google, Inc., Mountain View, California, USA
7. Mantle Labs Limited, London, UK